Division 4 — LOCAL LIMITS AND CATEGORICAL STANDARDS

(a)

Local limits are established to protect against pass-through and interference. No industrial user shall discharge wastewater to the sewer system in excess of the local limits established by the applicable control authority or adopted by the city. It is unlawful for an industrial user to discharge wastewater to the sewer system that exceeds either the local limits or that results in the inability of the applicable control authority to meet its NPDES permit requirements. Modifications to the local limits may be necessary to meet the requirements for discharge to the POTW or for basin groundwater recharge.

(b)

Discharges from industrial users subject to categorical standards shall be limited to the more stringent of the local limits or the applicable categorical standards.

(c)

The public works director may specify a mass limit for any pollutant in a wastewater discharge permit. Any mass limit shall be based on the local limit or categorical standard, whichever is stricter, and the user's average daily wastewater discharge. The average daily wastewater discharge shall be based on the previous 12 months of operation or other representative data. The public works director may revise the mass limit previously established in the user's wastewater discharge permit at any time, based on the user's current or anticipated operating data, and the city's ability to comply with any agreement with the applicable control authority and the requirements of any other regulatory agency. The excess use of water to establish an artificially high flow rate for mass emission rate determination is prohibited.

(d)

In order for the POTW to remain in uninterrupted compliance with mandated changes in federal, state or local requirements, the city shall adopt any required changes to the local limits.

(e)

The public works director may specify an electrical conductivity limit of 1,075 micro-Ohms per centimeter in lieu of the TDS local limit, if there is reason to believe that there may be significant interference with the analytical procedure to determine TDS.

(f)

The public works director may develop best management practices (BMPs), by ordinance or in wastewater discharge permits, to implement local limits or other pretreatment requirements.

(Ord. No. 1984, § 2(Exh. A), 3-10-26)

(a)

Maximum daily wastewater flow up to 50,000 gallons per day. No person shall discharge or cause to be discharged to the POTW wastewater characterized by a pH less than 5.0 or greater than 10.0.

(b)

Maximum daily wastewater flow exceeding 50,000 gallons per day. No person shall discharge or cause to be discharged to the POTW wastewater characterized by a pH less than 6.5 or greater than 9.0 at a maximum daily flow exceeding 50,000 gallons per day.

(Ord. No. 1984, § 2(Exh. A), 3-10-26)

(a)

Upon the effective date of a categorical standard (subpart I of 40 CFR chapter 1, subchapter N, Parts 405-471, as it exists and as it may be amended, or other applicable federal standard for a particular industrial category), the categorical standard shall, if more stringent than limitations imposed under this article for sources in that category, supersede the limitations imposed under this article. The public works director shall notify all affected users of the applicable limitations and reporting requirements.

(b)

Where a categorical standard is expressed in only terms of either the mass or the concentration of a pollutant in wastewater, the public works director may impose equivalent concentration or mass limits.

(c)

When the limits in a categorical standard are expressed only in terms of mass of pollutant per unit of production, the public works director may convert the limits to equivalent limitations expressed either as mass of pollutant discharged per day or effluent concentration for purposes of calculating effluent limitations applicable to individual industrial users.

(d)

When wastewater subject to a categorical standard is mixed with wastewater not regulated by the same standard, the public works director shall impose an alternate limit in accordance with 40 CFR 403.6(e).

(e)

Once included in its permit, the user must comply with the equivalent limitations developed in this section in lieu of the promulgated categorical standards from which the equivalent limitations were derived.

(f)

Many categorical standards specify one limit for calculating maximum daily discharge limitations and a second limit for calculating maximum monthly average, or four-day average, limitations. Where such standards are being applied, the same production or flow figure shall be used in calculating both the average and the maximum equivalent limitation.

(g)

Any industrial user operating under a permit incorporating equivalent mass or concentration limits calculated from a production-based standard shall notify the public works director within two business days after the user has a reasonable basis to know that the production level will significantly change within the next calendar month. Any user not notifying the public works director of such anticipated change will be required to meet the mass or concentration limits in its permit that were based on the original estimate of the long-term average production rate.

(Ord. No. 1984, § 2(Exh. A), 3-10-26)

Secs. 23-139—23-160. - Reserved.